Television distribution system for signal substitution

ABSTRACT

A cable television distribution system in which the head end substitutes different channels for a plurality of separated geographic zones. The head end creates a plurality of channel spectrums and transmits the spectrums on distribution trunks such that a different spectrum may be present on each distribution trunk. The spectrums on the distribution trunks are connected to zones of the viewer community which have been selected for market research purposes on the basis of demographics.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to the accumulation of panelistresponse information and more particularly to the presentation ofselected information to viewers of targeted television programming andthe accumulation of responses from those viewers.

[0002] Conventional market research has involved subjecting selectedgroups of consumers to particular promotional material and observingtheir responses. There have, however, been difficulties peculiar to theexposing of the selected group to particular promotional material aswell as problems peculiar to measuring their responses. A particularproblem is that the method of exposure of the selected group to thepromotional material or the collection of the responses may skew theresults; that is, the testing itself may influence the resultsindependently of the material being tested. More particularly, inrespect to the dissemination of television advertisements, if thepanelists know they are receiving special promotional material, they mayreact differently than were they to believe they are receiving normalpromotional material. Further, the participating panelists must bedivided into a control group and a test group receiving alternativematerial, and it is important that these groups be split so that thecontrol and test groups are matched on relevant statistics.

[0003] In respect to television advertising, one approach has been touse cable television with a split cable as illustrated by U.S. Pat. No.3,366,731, issued Jan. 30, 1968 to Edward Wallerstein for TelevisionDistribution System Permitting Program Substitution for SelectedViewers. In such a split cable system two cables originating from asingle transmitting source go out in different directions. Oneadvertisement is inserted on one cable and another advertisement onanother cable. A problem that has developed with this is that the splitof the cable produces control and test groups that are not properlymatched for market testing. This is, the two cables are directed todifferent neighborhoods at the whim of the cable television company,whereas the needs of market research are more particular. It has beenknown to provide two cables side by side, so that both cables serve thesame neighborhoods and are, therefore, likely to provide a better matchof control groups to test groups. However, even here there is a problemthat once the cables are laid the cables themselves select the groups;that is the television viewers are either on cable A or on cable B anddo not admit of special selection to meet the needs of a particularmarket test.

[0004] Another television market research system is shown in U.S. Pat.No. 4,331,973 issued May 25, 1982 to Eskin et al. With the Eskin et al.system, a substantially identical spectrum of television channels isprovided to all potential viewers. Some channels of the spectrum areused to convey possible substitute signals which are not accessible tomost viewers. The panelists of the system are given uniquely addressablepanelist receiving stations. When panelists are to receive substitutesignals, the unique addresses of their respective receiving stations aresent out to control the receiving stations to tune to the substitutesignals in place of the normal signals that others will watch.

[0005] The Eskin et al. system allows a different combination ofpanelists to be selected for each program substitution and has providedvaluable marketing information. The system, however, requires greatexpense in providing and maintaining sophisticated receiving stations ineach panelist household. Also, panelists at times resist the requirementfor such receiving stations in addition to their VCRs and cabletelevision distribution and decoder boxes which already connect to theirtelevisions.

[0006] A need exists for a market research signal substitution systemwhich accurately represents the demographics of the community beingserved and which avoids the problems, costs and user resistance of anindividually addressed arrangement.

SUMMARY OF THE INVENTION

[0007] In accordance with the present invention, the target community isdivided into a significant plurality of zones of coverage. In thedisclosed exemplary embodiment the number of zones is 24. The cable headend produces a small plurality of distribution trunks conveying normaland substitute channel signals in a cable television distributionspectrum. Each distribution trunk is split into a plurality of cabletelevision signal feeds which convey substantially identical signals totheir source distribution trunk. Each zone receives a cable televisionfeed signal from the cable television head end, which feed signal isdistributed to the viewer households of its respective zone. The marketresearch firm, prior to connection of feed signals to the zones,determines from information provided by volunteer panelists, whichcombination of zones throughout the community will demographicallyreflect the community as a whole or reflect a desirable attribute of thecommunity. Based on such a determination the zones are selected andconnected by cable signal feeds to one of the distribution trunks of thecable head end. The cable television head end equipment, in conjunctionwith equipment provided by the market research firm, from time to timeproduces at least one distribution trunk television signal spectrumhaving at least one substitute channel signal and at least onedistribution trunk television signal spectrum having channel signals notincluding the substitute channel signal. Based on the predeterminedconnection of distribution trunks to zones via the signal feeds, anormal spectrum is distributed to some zones while a substitutedspectrum may be delivered to other zones. A market research computersystem stores the associations of panelists with the particulardistribution trunks from which each panelist receives signals andanalyzes panelists' shopping behavior based on the signals presented topanelists' zones.

[0008] Each panelist in the study is assigned a panelist identificationwhich may be in the form of a panelist identity card. When a panelistpurchases goods, the panelist identification is associated with theinformation identifying the goods purchased and forwarded to a marketresearch computer system. The market research firm collects theassociated panelist-purchased goods information in the market researchcomputer system which has previously been informed of which panelistsare served by which zones and which zones have been provided atelevision spectrum signal feed including normal and substitute channelspectrums. Marketing information can then be generated based on thepurchases of panelists which did and did not receive the substitutechannel programming.

[0009] The panelist responses may be obtained without any consciousaction by the panelists. More particularly, in one embodiment all thepanelists need do is provide initial demographic data and to identifythemselves at the time of purchase of products. Otherwise they actentirely in accordance with their usual practices. Such identificationmight occur, for example, when the panelist uses his or her credit cardfor the purchase. More particularly, for grocery products at least,universal product coding (UPC) has become common. In accordance with theembodiment of the present invention, each panelist is provided with apanelist identification card having a scannable identification thereonwhich is recorded in a market research computer system to correspondwith the particular cable signal feed and thus which programming thepanelist has reviewed. The identification card is presented to thecooperating retail stores where he or she shops, where the card isscanned by a UPC product scanner along with the scanning of purchasedproducts. The work load of the panelist is reduced merely to presentinghis identification card. Data capture is electronic and automatic, bothfor the product and for the panelist identification. The panelist neverneeds to record anything. All data are recorded by the UPC scanner. Theinformation obtained by the scanner is transmitted by the retail storeto a market research computer system for association and correlation ofthe data with the advertisements sent out to the respective panelists.That is, the signals transmitted to the respective panelists areidentified as the signals sent out by the cable television head end, andthe responses of the respective panelists are noted by the scanningunits of retail stores and transmitted back to the market researchcomputer for association and correlation.

[0010] For best association and correlation it is helpful to have anarea blanketed with UPC scanners connected to the system. For example,if all of the grocery outlets, or substantially all, in a givengeographical area near the panelists are provided with UPC scannersconnected to the market research computer, substantially all groceryproducts purchased by the respective panelists are accounted for. Ingeneral, the retailers have substantially no adjustment to make beyondnormal scanning, except for scanning panelist identification cards.

[0011] A second embodiment of panelist purchase data collection may alsobe employed. In the second embodiment, the panelists regularly report tothe marketing research computer system their panelist identification anddata regarding the purchases they have made. For example, a panelist maybe provided with a home UPC scanner which is used to record recentpurchases. The purchase information and the panelist identity are storedin the home UPC scanner and transmitted to the market research computersystem where they can be analyzed in the same manner as the retail storecollected data. Many possible ways of data collection may be employedwith the present system provided that the panelist identity and theproducts purchased are matched before market research analysis.

[0012] It is an object of the present invention to provide panelistresponse scanning by the combination of a targetable television systemfor directing specific messages to groups of panelists in zones of thecommunity, a plurality of panelist identification means for identifyingrespective panelists, data collection arrangements for identifying theproducts purchased by respective panelists, and market research computersystem for receiving the information from the plurality of product datacollection arrangements to provide such automatic indication of panelistbehavior.

[0013] The system of the present invention provides results drawn fromselections of panelists in the community as a whole and does not merelyrepresent an unscientifically selected one-half of the community as doesthe Wallerstein arrangement and does not require the expense andcomplications of the per-panelist-directed system of Eskin et al.

[0014] In the present discussion, the term “panelist” is used torepresent the individuals in a particular household. The term “normal”is used herein to signify the messages, signals or programs provided bythe operation of the television system in the absence of thesubstitution provided by the present invention. It thus may encompassall messages, signals or programs as may be provided in the normalcourse of television programming, including special messages, signals orprograms transmitted and received over the usual channels to which thereceivers are ordinarily tunable. The term “program” encompassescommercials and other special messages.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a general block diagram showing a cable television headend constructed to deliver cable television signals, includingsubstitute signals to a community divided into zones;

[0016]FIG. 2 is a block diagram of a first embodiment of a cabletelevision head end;

[0017]FIG. 3, shows an rf cable splitter and a plurality of fiber opticdrivers;

[0018]FIG. 4 is a block diagram of a second embodiment of a cabletelevision head end;

[0019]FIG. 5 shows an addressable switch bay used in the embodiment ofFIG. 4; and

[0020]FIG. 6 is a block diagram of a third embodiment of a cabletelevision head end.

DETAILED DESCRIPTION

[0021]FIG. 1 is a general block diagram showing a targeted televisionsystem in accordance with the present invention for delivering cabletelevision signals to a viewer community represented by irregular area101. Twenty-four zones, of which only zones 103 through 108 have beennumbered, make up the community. Each of the zones represents an area ofthe community in which the cable television subscribers are served froma single cable feed such as cable feeds 109 and 111. The zones will notbe as regular as shown because they are determined by the cabletelevision company based on the economics of providing cable services.Each zone, however, includes a number of geographically proximatesubscribers and is referred to herein as being substantially contiguous.Further, it is possible that over time the zone boundaries will changeas new subscribers request cable service and other subscribers give uptheir prior service.

[0022] Each zone, e.g. 103, includes a signal distribution point such as113 which receives the cable feed, e.g. 109 and distributes the cable TVspectrum of the cable feed by means well known in the art to the viewersin the zone. The spectrum of signals on a cable feed, e.g. 109, isprovided by a cable head end 123. Cable head end 123 includes aplurality of signal inputs 125 for receiving the normal TV channels fromover-the-air broadcasts or satellites. It should be mentioned that thenormal channels may also include programming which is provided by thecable TV operator, such as video tapes of community events. The sourcesof normal signals, e.g., 125, are signal inputs to a television channelconnection apparatus 127, as are a plurality of input signals 128 from asubstitute channel signal source 129. In addition, the channel connector127 provides a plurality of normal TV channels to the substitute signalsource 129 over a plurality of connections 131. Substitute signal source129 and connection apparatus 127 cooperate under the control of acomputerized controller 135 to produce television signals for threedistribution trunks 142, 143 and 144. Each of the distribution trunks142, 143 and 144 conveys a full spectrum of cable TV channels to arespective splitter/driver 137 which includes an 8-way signal splitter126 and cable feed drivers, e.g. 122, 124 (FIG. 3). By the operation ofsubstitute signal source 129, connector apparatus 127 and controller135, the television channel signals may be different on each of thedistribution trunks 142, 143 and 144, so that the feeder cables 119 and121 may be carrying normal and substitute channels while the feedercables 117 and 115 of splitter/driver 139 and the feeder cables ofsplitter/driver 141 may convey only normal channels.

[0023] When a market research firm begins business in a community, thepopulation is solicited to identify cable television subscribers whoagree to participate as market survey panelists. As a part of acceptanceas panelists, such volunteers provide the market researcher withdemographic data comprising information about various types of personaland shopping behaviors. For example, the volunteers may disclose thenames and ages of individuals in the panelist's household, householdincome and likes and dislikes, as well as, the stores frequently shoppedand the brands frequently purchased. Based on the survey data the marketresearcher can determine the traits of the panelist for later use inanalyzing market research data. Also based on the panelist-providedinformation, the market researcher determines which of the zones, e.g.103-108, should be connected to which of the splitter/drivers 137, 139and 141. The goal is to demographically select the interconnectionbetween distribution trunks and zones so that each distribution trunk isconnected to a “cross section” of the panelists in the community. Forease of understanding, not all 24 feed cables from splitter/drivers 137,139 and 141 to zones have been shown. Instead, the signal distributionpoint, e.g., 113, of each zone has been given a letter A, B or C whichcorresponds to the A, B or C letter assigned to the splitter/driverconnected thereto. In FIG. 1, all 8 of the zones having a signaldistribution point labeled A, e.g., 151, 152 and 153, are connected tosplitter/driver 137, all 8 distribution points labeled B, e.g., 154, 155and 156, are connected to splitter/driver 139 and all distributionpoints labeled C are connected to splitter/driver 141. The describedmethod of selecting interconnection permits a demographic selection of atest group, e.g. A, for a new (substitute) advertisement, while anothergroup, e.g., B, can be selected as a control group which receives normalsignals rather than the new substitute advertisement.

[0024] The connection apparatus 127 receives all channels of normalsignals and substitute channel signals and combines the received channelsignals onto the three distribution trunks 142, 143 and 144. In thepresent embodiment each cable subscriber receives a spectrum of up to 60different channels on the cable at their household. During normaldistribution the channel signals from receivers 125 are properly channelmodulated and combined as a distribution channel spectrum on all threedistribution trunks 142, 143 and 144 such that all three trunks conveythe same signals. Each of the distribution trunks 142, 143 and 144 feedsan associated eight-way splitter/driver 137, 139 and 141. Thesplitter/drivers, e.g., 137, comprise an eight-way rf splitter 126, eachoutput of which feeds a fiber optic driver 122, 124. The output signalsof the splitter/drivers are then conveyed to connected distributionpoints, e.g. 151 and 152, via feeder cables 119 and 121. Thedistribution points convert the optical channel information back to rffor distribution to the subscribers in the zone. It should be mentionedthat at least two distribution trunks and splitter/drivers are used sothat a test group and a control group can be created. While the presentembodiment uses three distribution trunks, some panelist responsetesting systems may use four or more distribution trunks andsplitter/drivers. Also, the present embodiment uses fiber optic feedercables; however, other types of feeder cables, such as rf coaxial cable,could be used.

[0025] When a new advertisement is to be tested it is installed atsubstitute signal source 129 and made available on a lead 128 as aninput to the connection apparatus 127. Under the control of controller135 connection apparatus 127 replaces normal signals in a channel on oneof the distribution trunks 142, 143 and 144 with the new advertisement.When the substitution is made for distribution trunk 142, the substitutesignal is delivered to all subscribers, including all panelists, inzones A. Thus the panelists in zones A are the test group and thepanelists in either zones B or zones C, which do not receive the newadvertisement, may be chosen as a control group.

[0026]FIG. 2 shows an embodiment of a cable head end which is equippedto provide channel substitution in the manner described above for a 60channel distribution system. With the present embodiment twelve channelsmay be subject to signal substitution, while the remaining 48 channelsare not subject to signal substitution. For ease of understanding the 12substitutable channels are channels 2-13 while the other channels are14-61. Other combinations of channels could easily be used. FIG. 2includes forty-eight signal inputs 125B which are shown as off-airantennas but could be satellite receivers or inputs resulting from localTV cameras or VTRs. Each signal input is at base band or is converted tobase band by a respective demodulator of which demodulators 171 and 172are shown. The base band output of each demodulator is then modulated bya respective fixed channel modulator of which modulators 174 and 175 areshown. Each of the forty-eight modulators is tuned to a different outputchannel so that the outputs of all modulators 174, 175 comprises theforty-eight channels 14-61. The output signals from each modulator arecombined by a head end combiner 177 into a spectrum of channels 14-61.Combiner 177 splits the spectrum of channels 14-61 into three identicalcopies on outputs 179, 180 and 181 which are each applied to a separatetwo-way combiner 183, 184 and 185. The other input to combiners 183-185consists of channels 2-13, which are subject to signal substitution. Theoutputs of combiners 183, 184 and 185 are the distribution trunks 142,143 and 144, respectively.

[0027]FIG. 2 includes twelve normal channel signal inputs 125A which, asdescribed below, are subject to being replaced by substitute channelsignals through the use of a base band switch 187. As with channelinputs 125B, channel inputs 125A are shown as off-air signals but othersignal types may be used. Each channel input 125A is demodulated to baseband in a respective demodulator, e.g. 189, 191, which is connected viacables 192 as an input to base band switch 187. Up to six substitutechannels, at base band, are also connected from the market researchersas inputs 193 to base band switch 187. It should be mentioned that thesubstitute channels may also include test signals which can be switchedback to the market researchers for equipment testing on outputs 194. Thebase band signals switched back to the market researchers on conductors194 may also include a selected normal channel so that the substitutesource can be synchronized with the normal channel before channelsubstitution occurs.

[0028] Base band switch 187 responds to control signals from controller135 to selectively connect the inputs 192 and 193 to the outputs of theswitch. The outputs of base band switch 187 comprise outputs 194 to themarket researchers and outputs 195 which are used to complete thechannel spectrum sent to subscribers via distribution trunks 142-144. Toprovide a complete spectrum of channels 2-61 on each distribution trunk142-144, three fixed channel modulators for each channel 2-13 areconnected to outputs 195 of the base band switch 187. In FIG. 2modulators 161, 162 and 163 for channel 2 are all shown connected toseparate outputs 195 of base band switch 187, as are modulators 168, 169and 170 for channel 13. Three combiners 197, 198 and 199 are used togenerate three channel 2-13 distribution spectrums which arerespectively connected as inputs to the two-way combiners 183, 184 and185. Each combiner 197-199 receives twelve channel inputs, one for eachof the channels 2-13. In FIG. 2 combiner 197 is connected to channel 2modulator 161, channel 13 modulator 168 and to one modulator (not shown)for each channel 3-12. When connected as described, the distributiontrunks 142-144 have a channel spectrum from channel 2 to channel 61 andthe content of channels 14-61 is taken substantially directly frominputs 125B and the continent of channels 2-13 is taken from switch 187.

[0029] During nonsubstitution, the cable service provider or the marketresearchers instruct switch 187, by means of controller 135, to connecteach input signal 125A to all three of the modulators, e.g. 161, 162 and163, for that input signal. Thus, all cable subscribers will receive allnormal channels 2-61 from their connected distribution trunks 142-144.When a substitution is to occur, for example, on channel 2 forsubscribers connected to the A feed, the market researchers controlswitch 187 to connect the normal channel 2 signal to the marketresearchers via paths 194 as well to the three channel 2 modulators 161,162 and 163. The market researchers obtain synchronism information forchannel 2 from the channel 2 signal which they receive on path 194. Atthe moment for signal substitution, the market researchers send thesubstitute new advertisement to an input, e.g. 193 a, of switch 187which is controlled to connect the input 193 a receiving the substitutesignal to the output connected to modulator 161. The exact moment ofsubstitution is determined from the synchronism information receivedfrom normal channel 2, as is well known in the art. While the substituteadvertisement is being input to switch 187 it is fed on channel 2 to allsubscribers, including panelists, connected to distribution trunk 142.Those panelists connected to distribution trunks 143 and 144 continue toreceive normal channel 2 signals from inputs 125A. At the end of channelsubstitution, switch 187 is controlled to disconnect input 193 a and toconnect the channel 2 input signal directly from input 125A to modulator161. During the time of signal substitution, the substitution signalsare sent to approximately one-third of the cable subscribers. Given thedemographic selection of which zones are connected to the distributiontrunks, a proper test group of panelists has received the substitutesignals. Similarly, the panelists connected to distribution trunks 143and 144 have received the normal signals and can form the control group.

[0030]FIG. 2 shows a market research computer system 145 which isconnected to the market research organization, the scan networks 159 oflocal retail stores, to the telephone network 160 for other panelistinformation and to the controller 135. The market research computersystem, which may comprise multiple computers, stores lists of thepanelists connected to each of the distribution trunks 142-144. Duringsignal substitution it is informed by the researchers, on which trunkthe substitute commercial was carried. The market research computersystem 145 can use this information to evaluate panelist data collectedat local retail stores.

[0031] In the description of FIG. 2, base band switch 187 has been shownto include 12 input signal 125A ports and 6 substitute signal inputports as well as 36 channel output ports and a plurality of marketresearch output ports 194. It should be mentioned that othercombinations of substitute and normal signal inputs and other numbers ofchannel output ports 195 can be used. Although a larger base band switch187 would be needed, the system of FIG. 2 could include, for example, 18input sources 125A, and 9 substitute sources 193. Such a system wouldrequire 54 (3×18) output ports 195, each with a fixed channel modulatorsuch as modulator 170.

[0032]FIG. 4 shows a block diagram of a cable head end system which maybe used as an alternative to the cable head end system of FIG. 2. Thesystem of FIG. 4 provides the three distribution trunks 142-144 eachconveying a spectrum of 60 cable TV channels. The signals of any of the60 channels may be substituted in the manner described below. 60 inputsignal sources 125 are used in the system to provide signals for allchannels. Although the input signal sources are shown as off airantennas, they may be cable feeds, satellite receivers or VTRs, as iscommon in the provision of cable TV services.

[0033] The input signals from sources 125 are demodulated (171, 172) ifreceived at rf, and each is modulated to the frequency of a unique oneof the 60 channels 2-61 in respective modulators. Of the 60 modulators,only two are specifically shown, e.g., 173, 175. The output of eachmodulator, e.g. 173, is applied as an input to a four-way splitter, e.g.201, 203. Accordingly, 60 four-way splitters 201, 203 are present in thesystem. One of the outputs of each four-way splitter is connected by rfcable to a channel group combiner 208. In FIG. 2, cable 205 connectsfour-way splitter 203 to group combiner 208 and cable 206 connectsfour-way splitter 201 to the channel group combiner. A broad verticalline 240 represents a bundle of individual coaxial cables, eachconveying one modulated channel. The channel group combiner 208 thusreceives 60 rf cables each conveying signals from one of the inputsignal sources 125 in a unique television channel. A plurality of cablechannel combiners (not shown), as are well known in the art, make upcombiner 208 which combines all received channels onto a single 60channel spectrum on an rf coaxial cable 209. A signal splitter 211receives the channel spectrum on cable 209 and splits the spectrum intoa plurality of identical copies. As will be seen, the number of copiesrepresents the number of channels on which signal substitution can besimultaneously occurring. The present embodiment allows 6 channels to besimultaneously substituted, which results in splitter 211 being aneight-way splitter with two outputs unconnected.

[0034] Each of the six active outputs of splitter 211 is connected to afrequency agile demodulator (FAD) of which 213 and 215 are shown in FIG.4. The frequency agile demodulators receive control signals fromcontroller 135, via a control bus 235, which determine the particulartelevision channel they are to receive and demodulate. For example,demodulator 213 may receive from controller 135 signals defining channel2 and demodulator 215 may receive signals defining channel 17.Thereafter, demodulators 213 and 215 demodulate the signals in channels2 and 17 of cable 209, respectively, and apply the resulting base bandsignals as inputs to a video switch 217.

[0035] In the present embodiment video switch 217 is a twelve input bytwelve output switch which connects signals at the input ports to outputports defined by controller 135. Six input ports are connected to thebase band output signals of the frequency agile demodulators 213, 215and six inputs are connected to base band signals from six substitutesignal sources, of which sources 219 and 221 are specifically shown inFIG. 4. Six of the twelve output ports of video switches 217 areconnected to frequency agile modulators (FAM) of which frequency agilemodulators 223 and 225 are shown. The remaining six outputs of videoswitch 217 are connected by leads 226 as inputs to a vertical blankinginternal (VBI) timing unit 227. VBI unit 227 identifies timinginformation, including vertical blanking information, from each signalon leads 226 and is interrogated from time to time by controller 135. Onthe basis of the synchronizing information, switching can be commandedby controller 135 during the vertical blanking interval.

[0036] Frequency agile modulators 223, 225 respond to commands receivedfrom controller 135 via bus 235 to modulate base band signals receivedfrom video switch 217 to a television channel identified in the commandfrom the controller. For example, frequency agile modulator 223 may becommanded to generate output signals modulated to channel 2 andfrequency agile modulator 225 may be commanded to generate outputsignals modulated to channel 17. When output signals in another channel,e.g. channel 9, are needed, new commands are sent to an availablemodulator, e.g. 213, to change its modulation frequency to channel 9.The output of each frequency agile modulator is applied to respectivethree-way splitter of which three-way splitters 237 and 238 are shownconnected to modulators 223 and 225, respectively.

[0037] The embodiment of FIG. 4 includes three switched combiners 245,246 and 247, each of which is connected to receive an input cable fromall 60 four-way splitters 201, 203 representing input signals and isconnected to the three-way splitters 237, 238 conveying channelsmodulated by the frequency agile modulators 223 and 225. Thus eachswitched combiner 245, 246 and 247 is connected to Δ66 coaxial cables,each conveying signals modulated to one cable TV channel. Each switchedcombiner comprises 6 addressable switch bays 250, each comprising 12single pole, single throw rf switches labeled J1-J12 in FIG. 5. Theswitch bay also includes an address decoder with a manually settableaddress 251 and a connection 253 to the control bus 235. The addressdecoder responds to address commands from controller 135 by turning oneof the switches J1-J12 on or off as specified in the command. After acommand to enter a state, a switch remains in that state until commandedto change state. The outputs of the switches J1-J12 are connected asinputs to a plurality of rf combiners which are connected to produce aspectrum of TV channels 2-61 on a distribution trunk, e.g. 142. As shownin FIG. 4, the switched combiners 245, 246 and 247 generate a spectrumof TV channels on distribution trunks 142, 143 and 144, respectively.

[0038] The spectrum of channels applied to any of distribution trunks142, 143 and 144 is determined by the individually addressable switchedcombiners 245, 246 and 247. When only normal channels from input signals125 are to be sent on distribution trunk 142, switched combiner 245receives addressed commands from controller 135 to turn on all 60switches connecting the input signal sources 125, via their respectivechannel modulators, to the distribution trunk. The other switches ofswitched combiner 245 are turned off. When a signal is to be substitutedin a given channel on distribution trunk 142, switched combiner 245 iscommanded to switch the given channel from input signals 125 off and thesubstitute signal from video switch 217 (in the given channel) on.Controller 135 performs such switching on and off during the verticalblanking interval as identified by vertical blanking interval timingunit 227.

[0039] The following illustrates the delivery of substitute signals inchannel 17 on distribution trunk 142. Initially, all channels ondistribution trunk 142, including channel 17, are selected by switchedcombiner 245 from the input sources 125. At a time prior to actualsubstitution, controller 135 sends to an available frequency agiledemodulator, e.g. 215, a command specifying channel 17 and sends to anavailable frequency agile modulator, e.g. 225, a command also specifyingchannel 17. Controller 135 also sends to video switch 217 a commanddirecting that the switch input of frequency agile demodulator 215 beswitched to the switch output of frequency agile modulator 225. Afterfrequency agile demodulator 215, video switch 217 and frequency agilemodulator 225 have responded, a copy of the channel 17 signals frominput source 125 is available at the output of three-way splitter 238and at an input of vertical blank timer unit 227. Switched combiner 245is then commanded during a vertical blanking interval to turn off theswitch J1-J12 connected to the channel 17 input signal source 125 and toturn on the channel 17 input from three-way splitter 238. At this point,channel 17 is delivered to the subscribers connected to distributiontrunks 143 and 144 directly from the input source 125 and channel 17 isdelivered to the subscribers connected to distribution trunk 142 via thechannel group combiner 208 and video switch 217. When the time forsignal substitution occurs, as is recognized by an operator at themarket researcher, substitute signal source, e.g. 219, is started andcontroller 135 commands video switch 217 to connect the switch input ofsignal source 219 to the output connected to frequency agile modulator225. At the same time the prior connection between frequency agiledemodulator 215 and frequency agile modulator 225 is broken. Thisremoves the normal signals from channel 17 on distribution trunk 142 andreplaces them with the substitute signals from source 219. During thetime of signal substitution the substitute signal from source 219 willbe available on distribution trunk 142. At the conclusion of thesubstituted signal, the video switch 217 is commanded to reconnectfrequency agile demodulator 215 to frequency agile modulator 225 so thatthe continuing normal signal of channel 17 will be connected todistribution trunk 412. When all substitution for channel 17 iscompleted, switched combiner 245 is commanded to turn off the channel 17connection from the video switch 217 and to turn on the channel 17signal from the input sources 125.

[0040]FIG. 6, which comprises an alternative embodiment for the cablehead end, is largely the same as FIG. 4. With the system of FIG. 6, eachswitched combiner 245, 246 and 247 is directly connected to two of thefrequency agile modulators, e.g. 223 and 275. That is, the output ofeach frequency agile modulator is not split into three copies andapplied to all switched combiners as is done in the embodiment of FIG.4. In the system of FIG. 6, only two channels can be simultaneouslysubstituted on each of the distribution trunks 142, 143 and 144 and,when a signal is to be substituted on each of the distribution trunks142, 143 and 144, a switch path must be set up through video switch 217to a frequency agile modulator, e.g. 223, 225 and 276 connected to thedistribution trunk.

[0041] When replacing one channel signal with another, it is desirablethat both signals are of similar level so that subscribers will not beaware of the substitution. FIG. 6 includes signal sampling and amplitudecontrol apparatus to correct signal level mis-matches. Signal levels andgains throughout the system are controlled by fixed means so that thesignal levels from four-way splitters 201 and 203 are lower than thesignal levels from frequency agile modulators 223, 225 and 275-278. Anelectronically controlled attenuator 268-273 serially connects theoutput signals from the frequency agile modulators to their respectiveswitched combiners 245-247. Control for the attenuators 260-273 is sentby controller 135. The signals on each distribution trunk 142-144 aresplit by splitters 283-285, respectively, and communicated to a selector294 which also receives signals representing the outputs of attenuators268-273 which are taken by a plurality of splitters 291-286,respectively. Selector 294 comprises a selector switch having 9 inputs,one from each splitter 283-291, and one output 295. A carriermeasurement unit, which includes a controllable tuner and a carrieramplitude measurement unit (not shown), is connected to the output 295of selector 294.

[0042] When signals are about to be substituted, controller 135 directsselector 294 to connect a particular distribution trunk, e.g. 142, tocarrier measurement unit 296 and directs the tuner of carriermeasurement unit 296 to tune to the particular channel to besubstituted. The level of the carrier is then measured and signalsrepresenting that measurement are returned to controller 135. Similarly,selector 294 is controlled to connect the substitute channel splitter,e.g. 291, to the carrier measurement unit 296. Carrier measurement willoccur at the same channel carrier frequency as was measured from trunk142. The two measurements are compared by controller 135 which thendirects via bus 235 the relevant attenuator, e.g. 268, to attenuate thesignals at the output of frequency agile modulator 223 to the same levelas those sensed on trunk 142. Thereafter, the attenuation level providedat attenuator 268 will remain the same until a new substitution isproposed. It should be mentioned that the signal matching capabilitiesshown and described with respect to FIG. 6 are easily applied to theembodiments of FIGS. 2 and 4.

[0043] In the preceding embodiments, demodulators 171, 172, 189 and 191may be, for example, Scientific Atlanta Demodulator No. 6250, and mayinclude necessary receiving apparatus as is well known in the art.Modulators 161-163, 168-170, 173 and 175 may be, for example, No. 6350by Scientific Atlanta. The video switches 217 and 187 may be DynairSystem 21 routing switches configured with the required number of inputand output ports. Also, the embodiments describe systems having anexemplary number of cable channels and substitutable channels and signalsources. The number of channels and signal sources are discussed by wayof example and are not limited to those described. The precedingdescription relates to specific examples of systems embodying thepresent invention. The described systems can be modified by persons ofordinary skill in the art without departing from the spirit and scope ofthe present invention which is defined by the claims attached hereto.

What is claimed is:
 1. A television distribution system for delivering aplurality of channel signals in separated TV channels to a plurality ofcable television subscribers in a geographic area comprises, a cabledistribution head end comprising: a plurality of normal channel signalsources for producing normal TV channel signals to be delivered tosubscribers; a source of a substitute channel signal to be substitutedfor at least one normal channel signal; signal distribution circuitryfor receiving the normal channel signals and the substitute channelsignal and for combining the received channel signals into a spectrum ofchannels on a plurality of distribution trunks, the spectrum of channelson less than all of the plurality of distribution trunks including thesubstitute channel signal; and means for generating a plurality ofsubstantially identical copies of the spectrum of channels of eachdistribution trunk and the distribution system comprises: means forconnecting the substantially identical copies of the channel spectrum ofeach distribution trunk to different substantially contiguous zones ofthe geographic area.
 2. The television distribution system of claim 1wherein the means for connecting connects the spectrum of channelsignals from one of the distribution trunks to zones of the communityseparated from one another by zones connected to others of thedistribution trunks and selected to demographically represent thecommunity for market research purposes.
 3. A television distributionsystem in accordance with claim 1 wherein the zones connected to atleast one distribution trunk are selected to demographically representthe community for market research purposes.
 4. A television distributionsystem in accordance with claim 1 wherein a portion of the subscribersare market research panelists and each zone includes a plurality ofpanelists.
 5. A television distribution system in accordance with claim1 wherein the connecting means comprises fiber optic means forconnecting the substantially identical copies of the channel spectrum ofeach distribution trunk to different ones of the zones.
 6. A televisiondistribution system in accordance with claim 1 comprising a plurality offirst signal combiners equal in number to the number of distributiontrunks each first signal combiner receiving as inputs first channelmodulated normal signals for which no signal substitution is performedand second channel modulated signals including normal signals and atleast one substitute signal.
 7. A television distribution system inaccordance with claim 6 wherein the channels of the first channelmodulated signals are distinct from the second channel modulatedsignals.
 8. A television distribution system in accordance with claim 7comprising: a video switch apparatus for receiving as inputs, normalchannel signals and substitute channel signals and for selectivelyconnecting the input signals to a plurality of output ports of the videoswitch; and circuitry for combining the signals at the output ports intoa plurality of cable television channel spectrums equal to the number ofdistribution trunks.
 9. A television distribution system in accordancewith claim 8 comprising a plurality of channel modulators each connectedto an output of the video switch, the channel modulators comprising anumber of modulators equal to the number of distribution trunks for eachchannel of the second channel modulated signals.
 10. A televisiondistribution system in accordance with claim 1 comprising: a videoswitch apparatus for receiving as inputs, normal channel signals andsubstitute channel signals and for selectively connecting the inputsignals to a plurality of output ports of the video switch; andcircuitry for combining the signals at the output ports into a pluralityof cable television channel spectrums equal to the number ofdistribution trunks.
 11. A television distribution system in accordancewith claim 10 comprising a plurality of channel modulators eachconnected to an output of the video switch.
 12. A televisiondistribution system in accordance with claim 1 comprising: a pluralityof first signal conductors each for conveying a single channel modulatednormal television signal; at least one second signal conductor forconveying a single channel modulated substituted television signal; aswitched combiner means connected to receive signals from the firstsignal conductors and the second signal conductor for selectivelyconnecting signals from predefined ones of the first and second signalconductors to the distribution trunks.
 13. A television distributionsystem in accordance with claim 12 wherein the switched combiner unitcomprises a switched combiner for providing signals to each of thedistribution trunks.
 14. A television distribution system in accordancewith claim 13 wherein each switched combiner comprises a plurality of rfswitches, one rf switch for each of the first signal conductors and thesecond signal conductor.
 15. A television distribution system inaccordance with claim 14 comprising a video switch for selectivelyconnecting substitute channel signals and normal channel signals ontothe first signal and the second signal conductors.
 16. A televisiondistribution system in accordance with claim 14 comprising video switchmeans for selectively connecting substitute signal sources to the secondsignal conductor modulated to a predetermined channel.
 17. A televisiondistribution system in accordance with claim 15 comprising a frequencyagile modulator connected to an output port of the video switch formodulating substitute signals to a predetermined channel.
 18. Atelevision distribution system in accordance with claim 16 comprisingmeans for demodulating selected ones of the normal channel signals andmeans for connecting resulting demodulated signals as inputs to thevideo switch.
 19. A panelist response scanning system comprising aplurality of product scanning units for location at respective stores, atargetable television system serving a community of people, a pluralityof panelist identification means for identifying respective panelists,and a market research computer system for coupling to said productscanning units, said targetable television system including head endmeans, a signal distribution arrangement and a plurality of televisionreceivers, said head end means including means for transmitting normaltelevision program signals and substitute television program signals ona plurality of distribution trunks connected by the signal distributionarrangement to said plurality of television receivers, each televisionreceiver being connected to one of the distribution trunks preselectedso that a plurality of receivers connected to at least one of thedistribution trunks demographically represents the community for marketresearch purposes, the head end including means for selectivelysubstituting substitute program signals in lieu of normal televisionprogram signals for transmission of a substitute program on one of thedistribution trunks to the plurality of the television receiversconnected thereto, each of said respective stores having means forreceiving panelist identification information corresponding to a saidpanelist identification means and for receiving product identificationcorresponding to said products to produce transaction response signalsincluding panelist identification signals and product identificationsignals respectively identifying the panelists and the products upon thepurchase of products at the store, whereby the system is closed betweenthe targetable television system and the product scanning units by theacts of the respective panelists in viewing the programs presented onthe respective television receivers and presenting their correspondingpanelist identification to one of the respective stores upon making thepurchase of a product, said market research computer system includingmeans for identifying the particular panelist identifying informationassociated with each of the distribution trunks and responding to saidtransaction response signals to provide an indication of panelistbehavior in response to said normal and substitute programs.
 20. Apanelist response scanning system in accordance with claim 19 comprisingcontroller apparatus for controlling signal substitution on thedistribution trunks and for identifying such substitution to the marketresearch computer system.
 21. A panelist response scanning system inaccordance with claim 19 wherein the panelists are distributedthroughout a viewer community and the distribution means comprise meansfor splitting the signals on each distribution trunk into a plurality ofsubstantially identical copies and for conveying the signal copies byfiber optic means to demographically determined groups of panelists. 22.A panelist response system comprising a targetable television systemserving a community of people, a plurality of panelist identificationsfor identifying respective panelists, means for collecting panelistpurchase information, and a market research computer system, saidtargetable television system including head end means, a signaldistribution arrangement and a plurality of television receivers, saidhead end means including means for transmitting normal televisionprogram signals and substitute television program signals on a pluralityof distribution trunks connected by the signal distribution arrangementto said plurality of television receivers, each television receiverbeing connected to one of the distribution trunks preselected so that aplurality of receivers connected to at least one of the distributiontrunks demographically represents the community for market researchpurposes, the head end including means for selectively substitutingsubstitute program signals in lieu of normal television program signalsfor transmission of a substitute program on one of the distributiontrunks to the plurality of the television receivers connected thereto,the means for collecting panelist purchase information having means forreceiving panelist identification information and for receiving productidentification corresponding to products purchased by the panelist toproduce transaction response signals including panelist identificationsignals and product identification signals respectively identifying thepanelists and the products upon the purchase of products, whereby thesystem is closed between the targetable television system and thepanelist purchase information by the acts of the respective panelists inviewing the programs presented on the respective television receiversand providing their corresponding panelist identification and purchasedproduct information after making the purchase of a product, said marketresearch computer system including means for identifying the particularpanelist identifying information associated with each of thedistribution trunks and responding to said transaction response signalsto provide an indication of panelist behavior in response to said normaland substitute programs.
 23. A panelist response scanning system inaccordance with claim 22 comprising controller apparatus for controllingsignal substitution on the distribution trunks and for identifying suchsubstitution to the market research computer system.
 24. A panelistresponse scanning system in accordance with claim 22 wherein thepanelists are distributed throughout a viewer community and thedistribution means comprise means for splitting the signals on eachdistribution trunk into a plurality of substantially identical copiesand for conveying the signal copies to demographically determined groupsof panelists.